In recent years, image information is treated as digital information, and at that occasion, an apparatus is becoming widely prevalent that compresses and encodes an image by employing a coding method for performing compression by orthogonal transformation and motion compensation such as discrete cosine transform using redundancy unique to image information for the purpose of highly efficient transmission and accumulation of information. Examples of the coding methods include MPEG (Moving Picture Experts Group), H.264 and MPEG-4 Part 10 (Advanced Video Coding, hereinafter referred to as H.264/AVC), and the like.
Currently, for the purpose of further improving the encoding efficiency as compared with the H.264/AVC, a coding method called HEVC (High Efficiency Video Coding) is being standardized by JCTVC (Joint Collaboration Team-Video Coding) which is a joint standards organization of the ITU-T and the ISO/IEC (for example, see Non-Patent Document 1).
In the current draft of HEVC, sample adaptive offset (SAO) filter is employed. In the sample adaptive offset filter, control signals between components of Y, Cb, Cr are all transmitted independently.
In contrast, Non-Patent Document 2 suggests transmission upon replacing an ON/OFF control signal between components with a single syntax and transmitting the type of the filter and coefficients independently between components.